Back to the subject of how much it costs to ride the T, it is nice to see that in San Francisco they have the vision to let people ride for free to, among other things, decrease air pollution.

"The first free-ride offer by BART this year, offered June 22 because of high air pollution levels in the Bay Area, brought a 10 percent rise in ridership. A total of about 329,000 passengers -- 33,000 higher than the average Thursday ridership -- took the train on the first Spare the Air day declared by the Bay Area Air Pollution Control District. According to BART officials, having that many people leave their cars at home reduced pollution levels by 726 tons. "